Geometry jitters while animated along path
Turns out, this IS in fact a floating point precision issue.  Not something to do with the math along the path, itself.  In an effort to keep my vehicle and camera near the world origin, I created a root object, parented my environment and path to it, then animated it's location to try to keep the vehicle near to 0,0,0.  It has helped a LOT!  Here is a video, outlining the solution and result: http://sean.novak.us/vid/help/jitterSolution.mp4